A multitude of different communication terminals and devices have been developed for packet-based multimedia communication using IP (Internet Protocol), such as fixed or mobile computers and telephones, which will be generally called “user terminals” here for short. Multimedia services typically involve transmission of media in different formats and combinations. For example, a user terminal may exchange audio information as well as visual information with another user terminal, or may download or stream media in any format from a content server.
An architecture called “IP Multimedia Subsystem” (IMS) has also been developed as a platform for enabling multimedia services and sessions, commonly referred to as an IMS network or IMS core. Thus, an IMS network can be used to initiate and control multimedia sessions for any IMS enabled user terminals connected to different access networks. Although conceived primarily to enable multimedia services for mobile terminals, the IMS concept can be used for fixed terminals as well.
Multimedia sessions are handled by specific session control nodes in the IMS network, also called CSCF (Call Session Control Function) nodes including P-CSCF (Proxy CSCF), S-CSCF (Serving CSCF) and I-CSCF (Interrogating CSCF). An IMS network further includes a database node HSS (Home Subscriber Server) for storing various subscriber and authentication data, and typically also includes various application servers for enabling the multimedia services.
The communication protocol called SIP (Session Initiation Protocol) is generally used by IMS networks for controlling multimedia services, thus being a signalling protocol for creating, modifying and terminating sessions over a packet-switched logic. An application server of an IMS network is therefore commonly referred to as a “SIP-AS”.
FIG. 1 is a simplified schematic illustration of a basic network structure for providing multimedia services for a mobile terminal A by means of an IMS core 100. The terminal A is connected to a mobile access network 102 and communicates in a multimedia session with another terminal B which may be connected to the same access network 102 or another access network (not shown). The access network 102 is connected to IMS core 100 which comprises “CSCF nodes” 104 and a HSS 108. A plurality of application servers 106 are also attached to the IMS core 100.
Terminal A exchanges control messages with the IMS core 100 whereas data is communicated with terminal B over network 102 during the session, as shown in the figure. Terminal A may alternatively communicate with an external content server or the like, e.g. for downloading some multimedia content therefrom, or merely with one of the application servers 106.
The current standardised IMS services typically require the usage of a SIP-AS, including the services of MMTel (Multimedia Telephony) and IM (Instant Messaging). The full service logic of an IMS service is generally divided between the user terminal, the IMS core nodes and the SIP-AS. The user terminal is needed as a user interface and for basic application execution, and the IMS core nodes are used for finding and connecting terminals and servers with each other. The SIP-AS typically offers extra service logic beyond the basic services, e.g. supplementary services such as call barring.
However, IMS services can be fairly complex to accomplish and execute since several nodes are required as service logic points, e.g. the user terminals, core nodes, and various application servers such as the SIP-AS. Further, functionality in the nodes above and signalling there between are required for executing user-dependent control of services. No simple way has been described to avoid network processing and signalling when controlling outgoing calls for a terminal, e.g. if the terminal is shared by plural users where it may be desirable to differentiate the usage of the terminal.
EP 1775922 A1 discloses that a terminal user can configure a contact list in his/her terminal to bar incoming calls from certain calling parties.
WO 03/030579 discloses that when a base station receives a signal from a mobile terminal associated with a request for an outgoing communication, the base station checks rules in a database for the terminal to determine whether the outgoing communication can be allowed to go through.
WO 99/18704 discloses that a supplementary service (SS) database in an intelligence network (IN) node stores call barring data for controlling outgoing calls.
GB 2305073 discloses that a memory element in a mobile radio unit contains respective operational characteristics of a plurality of users. It is also briefly mentioned that the operational characteristics may include call barring details, among other things, without further description.